An ultrasonic diagnostic apparatus transmits ultrasonic waves from an ultrasonic probe to a subject, receives the ultrasonic waves reflected by the subject via the ultrasonic probe, and generates an ultrasonic image based on an echo signal corresponding to the received ultrasonic waves. The ultrasonic image includes various kinds of noise and speckle due to ultrasonic interference other than information concerning the subject tissue. Noise and speckle degrade the image quality of the ultrasonic image.
There is available a method of reducing noise and speckle and enhancing information concerning a subject tissue by calculating the edge information of each pixel of an ultrasonic image and applying a filter corresponding to the calculated edge information to each pixel. More specifically, this filter smoothes the information in the edge direction and sharpens the information in a direction perpendicular to the edge direction. The image processing method using the filter is used to improve, for example, the image quality of a blood vessel image.
In this filtering method, it is preferable to optimize a filter characteristic in accordance with the behavior of a living tissue in a diagnostic region. In the present circumstances, a set of parameters for determining a filter characteristic is set in advance for each diagnostic region. In this case, the operator selects a parameter set corresponding to a diagnostic region as a scan target on an operation window, and a filter corresponding to the selected parameter set is applied to an ultrasonic image.
In ultrasonic examination, when the operator moves the ultrasonic probe, the diagnostic region or living tissue depicted in an ultrasonic image sometimes changes. Even if a selected parameter set is suitable for a diagnostic region or living tissue before movement, the parameter set is not always suitable for the diagnostic region or living tissue after the movement. If a parameter set is not suitable for a diagnostic region or living tissue, filtering suitable for the diagnostic region or living tissue is not performed, resulting in a deterioration in image diagnostic performance.
It is an object of an embodiment to provide an ultrasonic diagnostic apparatus, a medical image processing apparatus, and a medical image processing method which can improve image diagnostic performance.